#include <iostream>
#include <random>
#include <sstream>
#include <iomanip>
#include <atomic>

static std::string uuid()
{
    std::random_device rd;
    std::mt19937_64 gernator(rd());
    std::uniform_int_distribution<int> distribution(0, 255);
    std::stringstream ss;

    for (int i = 0; i < 8; i++)
    {
        ss << std::setw(2) << std::setfill('0') << std::hex << distribution(gernator);
        if (i == 3 || i == 5 || i == 7)
        {
            ss << "-";
        }
    }

    // 添加序号
    static std::atomic<size_t> seq(1);
    size_t num = seq.fetch_add(1);
    for (int i = 7; i >= 0; i--)
    {
        ss << std::setw(2) << std::setfill('0') << std::hex << ((num >> (i * 8)) & 0xff);
        if (i == 6)
            ss << "-";
    }
    return ss.str();
}

int main()
{
    for (int i = 0; i < 20; i++)
    {
        std::cout << uuid() << std::endl;
    }

    // static std::atomic<size_t> seq(1);
    // size_t num = seq.fetch_add(1);
    // for (int i = 7; i >= 0; i--)
    // {
    //     std::cout << std::setw(2) << std::setfill('0') << std::hex << ((num >> (i * 8)) & 0xff);

    // }
    return 0;
}